Back it in
Braking isn't the same story, however. Even on standard Range Rover Sport four-piston calipers and discs it'll lock the wheels before I can say shhh... as we head for that large 100-year-old oak at an alarming rate. Sideways.
My heart rate increases the first time it happens, but once you realise you have to drive the car this way - set the attitude by backing it into the corner, then pick up the throttle and gun it out - it actually becomes perfectly natural. The driving style is infectious. On the way home I find myself thinking, "If I just use a bit of brake as I enter this roundabout..."
On-road in an off-roader
Unfortunately, the ECU of the finished EXR-S decided to throw a tantrum, so it was back into the prototype vehicle Mr Harris drove earlier in the year for my drive. It's different now, though. Immediately you notice the EXR-S prototype's suspension tweaks to improve its on-road manners and a mildly more representative interior of what the road car will get. Importantly though, the powertrain is exactly what the road car will get.
Harnessed in the leather bucket seat you look out over a Range Rover Sport steering wheel and clocks, but the ferocity of the noise emitted from the near straight-through side exit pipe is enough to blow small children over.
Hold on tight
I'm on Millbrook's mile straight doing a few 0-100-0 runs - stall the torque converter on the brakes, peel off the left hand pedal and hang on. The noise is fantastic - mechanical and rabid - and despite no form of traction control the EXR-S's rear axle digs in, with just the right amount of weight transfer to aid the launch. The front scrabbles around for grip but bites once it's off the line.
I just kiss 100mph and hit the brake pedal with everything I've got - the EXR-S prototype has ABS, only it doesn't use any clever stability systems to keep the rear wheels following the fronts. As that weight transfer comes into play again, this time unloading the rear, it squirms around like a toddler in a high chair. I'm forced to dial in a quarter turn of lock to catch it, but it still pulls up only a quarter of a mile after we set off - the normal Range would be sailing straight on here. But then it does weigh 725kg less than the 2.6-tonne Landy.
Then it hits me. The company has managed to condense that essence of ridiculous robustness from what it does on the rough stuff and package it into a road car with the perfect balance of rawness and refinement.
Company founder Drew Bowler keeps telling me, "It's all about performance, but people don't actually want a rally car on the road." I can tell. An autobox, light steering and acceleration to warp perceptions should make the £155,000 EXR-S a stonkingly capable - mental, even - but useable car.
Engine: 4,999cc V8, supercharged
Transmission: 6-speed auto
Power (hp): 550 @ 6,000rpm
Torque (lb ft): 461 @ 2,500 - 5,500rpm
0-62mph: 4.2 sec
Top speed: 155mph (electronically limited)
MPG: 15.0mpg (estimated)
Price: £155,000 (before options)